Ankle fusion is a routinely performed operation to relieve pain in the ankle due to bone or joint destruction from injury or disease. The prior art includes a variety of approaches used as well as a variety of fixation methods. All fixation methods require a standard debridement of the area to be fused; removal of cartilage, dead bone, and fibrous tissue to get good contact between healthy bone surfaces.
Presently, when the two bone halves are ready to be fixed together, the surgeon chooses a method to hold the two bones together until the bone can grow together. The prior art methods used include external fixation where pins stick out from the bones and are joined by external compression rods or frames. Simple screw fixation, much like in carpentry, can be used with the screw going from one bone to the other to lock the two pieces together. There are also a number of prior art metal plates (titanium or stainless steel) which can be applied to the exposed bone surface of the tibia and talus. The plates cross between the two bones and screws are used to fix the metal plate to each bone.
There are also so called “intramedullary nails” which are touted as “ankle fusion nails” but, in fact, do not meet the criteria for such a device as will be disclosed herein. To date, however, the prior art intramedullary nail is solid bar or hollow pipe that is placed in the center of the tibia or leg bone and travels in the medullary canal or inside the leg bone. The prior art nails, however, actually fuse both of the joints in the hindfoot as practiced. This is very detrimental to the long term survival of the foot. An advantage of the nail, however, is that it is wholly inside the leg bone and thus creates greater stability than an outside plate and creates a smaller lever arm for deforming forces. A very big disadvantage of the prior art nails, however, is that they destroy adjacent joints and they are not easily adjustable to provide appropriate and necessary compression of the two bones surfaces.
Thus, it is an object of this invention to provide an ankle fusion nail system and method that is an intramedullary device that provides stabilization and fixation during boney healing without violating surrounding joints, that does not fuse the whole hindfoot and that allows for a limited incision thus minimizing soft tissue damage. It is a further object of the invention to provide an ankle fusion nail that is adjustable such that the necessary compression of the two bone surfaces may be accurately and precisely applied by the nail itself.